The world-renowned economist’s findings shatter the main plank of the pro-Europe argument and add weight to the Daily Express crusade to get Britain out of the EU.

They come on the same day Prime Minister David Cameron makes a key speech setting out fresh details of the crucial areas he wants to change ahead of his in-or-out EU referendum.

Mr Cameron is also revealing his reform demands to the EU warning that the UK will vote to leave if they are ignored.

Professor Minford’s calculations, revealed to the Foreign Affairs Committee, showed that cutting ties with Brussels could be “life saving” for low-paid workers and pensioners, campaigners said.

William Dartmouth MEP, the Ukip trade spokesman said: “The EU costs each of us money every single day of our lives. What Professor Minford told the Select Committee must be taken very seriously indeed.

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Without Brussels, Brits would be better off

“It is becoming crystal clear that on Brexit we will quite literally be ‘Better Off Out’. Imagine the impact of an 8 percent drop in costs to pensioners, and those on the minimum wage. It could be life saving. It will certainly lighten their load significantly.”

Andy Wigmore of Leave.eu said: “This just goes to show that the impact on leaving the EU could have a dramatic effect on ordinary people and their cost of living which is hugely significant and of great importance to anyone who fears leaving the EU will be a dangerous option.

“It also demonstrates that the scaremongering from big business and the IN campaign is not justified. It tells voters that the world will not end if we vote to leave the EU and if anything just proves that all of us will be better off including small and medium business which represents 99 percent of companies in the UK.

“Big corporations will hate this report. I’m sure they will do everything to destroy its conclusion”

Professor Minford, the widely-respected head of the business school at Cardiff University, revealed the staggering cost of staying in the EU to MPs on the Foreign Affairs Committee.

He shrugged off the argument that Britain benefited from EU trade agreements saying we would be better off leaving the bloc and trading on the global market without Brussels-imposed restrictions on which countries it could deal with.

Switching from “EU prices” to “world prices” will mean importers can negotiate better deals for everyday items such as food and household goods making life substantially cheaper for Britons.

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Professor Minford shows that this could have a dramatic impact on people's lives

And exporters could sell their products for more money outside Europe, he said.

“It pays us to be a global player under free trade. It pays us to sell our goods to other people on the world market and take their goods at world prices. That will lower our cost of living.

“We have actually done a simulation of leaving the EU and the first thing that comes out is an 8 percent drop in the cost of living on day one because of the move from EU prices to world prices. “Now that is really worth having.”

The EU would want a signed trade deal with the UK if it left the bloc because its member states sell far more goods to Britain than the other way round, he warned.

“The last thing they will want us to do is to walk away without some sort of free trade agreement because they so depend on our market relative to our dependence on theirs.

“They are selling stuff to us at inflated prices on a massive scale compared to what we sell to them,” he said.

“What people are saying is that if we leave the EU it is disastrous, because we’ll lose leverage. “The truth is we’ll move, if we’ve got any sense, to a liberalised economy, fundamentally under free trade. It isn’t in our interest not to have free trade.”

The rules and regulations imposed on businesses by Brussels mean the cost to the UK was “very large,” he added.